Well pump and sprinkler problem

[Tom T]

Hello everyone. This is my first ever post and I'm hoping you guys can help me out. I have a 3/4HP Goulds jet pump that I use exclusively for my lawn sprinklers. The pressure switch is set to 30/50, and I believe the tank is 1 gallon. I have nine sprinkler zones on my property. My system has worked beautifully for 20 years which is how old our house and well/sprinkler system is. We have town water for our domestic use.

We recently had a pool installed along with a lot of landscaping and gardening work done. A lot of the sprinkler hoses were dug up, destroyed and so on. Our landscaper (who also does sprinkler work) re-worked our zones and our sprinkler heads. He also added a tenth zone for all the new trees and flower beds as a drip irrigation system. So we now have nine zones of traditional sprinklers and a tenth huge drip zone.

The problem now is that four out of our nine sprinkler zones are rapid cycling (every 5 seconds), as is the drip system. I hooked up a hose to the system to increase the flow to stop the cycling and simply have the water running into the street when those zones are working. This is obviously not sustainable. I called the landscaper/sprinkler guy, and he told me that I have to call a "pump guy" to take care of the problem and that his job is done. I never expected any of this.

I've been doing some research and I believe that the cycling in the sprinkler zones can be taken care of with a cycle stop valve. What can I do about the drip line? Are sprinkler systems and drip systems even compatible with one another on the same pump? Some insight would be greatly appreciated.

 

[WorthFlorida]

A CSV will help and may fix your problem. Depending on the CSV model, 1-3 gallons per minute of water flow is needed. Call CSV for the proper model needed.

The real problem is your using a jet pump with a pressure switch for irrigation. With the zones reworked they were reduced in size, therefore, the pump is providing more water than the zones can expel. A jet pump is only needed to be used if it is a deep well, below 25 ft static water table. An irrigation pump doesn't use a pressure tank or pressure switch.

What you can do for now is besure the small tank is drained and then pressurized to about 28 lbs empty. Another is you can combined two zones for more sprinklers per running zone. I have a Rain Bird ESP-E controller and I have two zones wired together after removing about a dozen sprinklers heads because of a major landscaping and a patio addition. The Rain Bird controller can handle two solenoids on one zone without a problem. Lastly, depending on your system layout, decrease the number of zone valves by repiping the sprinkler zones for larger zones. If all of the valves are next to one another such as a manifold setup, then it is easy to do.

Having a hose to dump more water onto the ground to stop the short cycling is OK. Just reduce the irritation time for those zones. Most controllers you can program four start times per zone per day. 30 minutes in the morning and 20 minutes in the evening is better than 60 minutes at one time. I find probably 90% over water the yard and landscaping. Other than grass, once shrubbery is establish, the water need is very small or none at all if there is regular summer rain showers.

 

[Sponsor]

 

[Banjo Bud]

Why do you even need a tank OR a pressure switch? I have a sprinkler system and no tank or anything. My pump draws directly from a shallow well and outputs to the sprinklers. I have 4 zones. The sprinkler control valve controls the pump on/off times. The pump outputs 40 psi at 15 GPM. My heads in each zone put out about 12 GPM combined. This means that my pump is restricted somewhat but that’s ok. It has worked fine for 9 years.

 

[Bannerman]

BB, if your pump can deliver 40 psi @ 20 GPM 15 GPM, then the pressure to 12 GPM sprinklers should then be higher than 40 psi. The restriction is OK as it will function similar to a Dole valve which will restrict the flow from the pump to the flow rate needed. As long as at least 1-zone is flowing, the pump will not dead-head.

For those that want water simply by opening a faucet, the pressure tank AND pressure switch will a!low the water distribution system to remain pressurized even while the pump is not operating. Simply opening a faucet will allow water flow which will cause the system pressure to become lower so the pressure switch will automatically activate the pump. . Once the system pressure rises sufficiently to the pressure switch cutoff pressure, the pressure switch will automatically shut off the pump until the next time water is utilized.


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[Banjo Bud]

Yes Bannerman that’s all true. My sprinkler pump is dedicated to sprinkling. It does nothing else. The OP did say that his pump is used exclusively for sprinkling

 

[Bannerman]

BB, because you are using your pump for only one purpose and you are not concerned with water availability to garden hose faucets, yard hydrants or other uses, you determined a constantly pressurized system is not essential. You have chosen to control pump operation with your irrigation controller so the controller will activate the pump only when your irrigation system is scheduled to operate.

If you required water for other than only the irrigation system such as garden hose faucets or yard hydrants at times that don't conform to the irrigation schedule, then you would need to manually activate the pump while also ensuring the garden hose or yard hydrant remains flowing while the pump is running. If you were using the well pump for those other uses, a pressurure tank/pressure switch would provide a safer and more convienient method to control pump operation.

Using a PT/PS control, the irrigation controller would not control the pump operation but would only control the individual solenoid valves utilized to control flow to each irrigation zone.

 

[Tom T]

Hey guys, thanks for the comments. If I were to simplify things and get rid of the pressure switch and tank, wouldn't those problem zones (especially the drip) have really high pressure that could damage the heads and hoses? Could I still put a cycle stop valve to choke off some of that flow to keep the heads from getting all that pressure? Also, if the flow is being choked off in that way, can that damage the pump? My drip zone is set to run for 1 hour twice daily and that motor gets really hot. Thanks again.

 

[Drick]

T.T, if your plan is to get rid of the tank and pressure switch you need to think about how you are going to handle the case of a zone valve failure. If one of your valves fails to open (ex. bad solenoid) the pump start relay will still activate the pump, but the pump will deadhead with moving no water. The pump won't last long like that. If you didn't have the drip zone I'd say you could could add a pressure relief valve to deal with a deadheaded pump, but the pressure differential between a deadheaded pump and the drip zone may be too small to get a relief valve to open and close properly.

Personally if a CSV will work with your pump and your drip zone I'd install it and be done with it. Find out from your landscaper how many gallons per minute your drip zone uses. As long as a CSV will work with your pump and your drip zone's GPM its enough to keep the CSV from cycling the pump you'll be in good shape.

To answer your questions, pumps aren't harmed by back pressure. As long as you are using enough water to keep the pump from overheating - approx 1.5gpm - the pump will be fine. If your pressure is too high on the zones that are short cycling you can add a pressure reducer after the zone valve. They also make pressure reducing valves. The drip zone should already have a pressure reducer on it but you should probably confirm that with your landscaper.

 

[Valveman]

A CSV will work with a pump start relay as well. When set at 50 PSI the CSV will still keep the pressure at 50 PSI no matter if it is a large sprinkler zone or a small drip line over 1 GPM. A pressure relief valve after the CSV and set at 60 -65 PSI will also protect the pump if the controller starts the pump and fails to turn on the sprinklers as drick mentioned.